The present invention relates to apparatus for transmitting torque between two relatively rotatable flywheels, particularly in the power train between the output element of the internal combustion engine and the input element of the change-speed transmission in a motor vehicle. More particularly, the invention relates to improvements in apparatus for transmitting torque in such a way that peaks of transmitted torque are eliminated with attendant prolongation of the useful life of the power train.
It is well known to provide one or more dampers intermediate the relatively rotatable flywheels of a power train between the crankshaft of the internal combustion engine and the input shaft of the change-speed transmission in a motor vehicle. The damper or dampers allow for a relatively small angular displacement of the flywheels relative to each other. In many instances, the means for transmitting torque between the two flywheels comprises energy storing elements in the form of coil springs which act in the circumferential direction of the flywheels and are installed to operate in parallel with friction generating or slip torque generating means.
A drawback of presently known apparatus for transmitting torque is that the energy storing elements (such as the aforementioned coil springs) of the damping means must perform relatively large movements between fully expanded and fully compressed positions in response to angular displacements of the flywheels relative to each other. Consequently, the length of the coil springs must be selected in such a way that they exhibit a relatively small amount of rigidity so that they cannot resist deformation under the action of centrifugal forces. Such deformation or flexing in the axial direction of the energy storing components cannot ensure adequate (predetermined) proping in the radial direction and/or an optimal application of force to their end convolutions during compression. The result is that the surfaces of contact between the energy storing springs and the adjacent parts of the apparatus are subjected to excessive wear which results in relatively short useful life of the energy storing elements as well as of the entire apparatus.